What hardware or model you are using to mine dash? is it antminer D3?
there is a good setup that you can follow from bitmain you can check it here https://bitmainhelp.zendesk.com/hc/en-us/articles/115002112313-Connecting-your-D3-miner-to-Antpool

Maybe you miss something that is why you are not getting rewards or you are just using other setup that is why you are not getting any rewards. check it carefully...